Liquid tight cord connectors are quite common for supporting electric wire passing through an aperture of an electrical enclosure or a wall. These cord connectors are often used to protect wires or tubes passing through such apertures against wear or shock or both.
FIGS. 1-7 of U.S. Pat. No. 2,458,409 discloses a connector member with integral spring-like fingers cooperating with and preventing axial movement of a cable member after it is inserted into the knockout hole through the connector member.
FIGS. 1-8 of U.S. Pat. No. 3,516,111 shows a bushing member having a plurality of flexible generally pie-shaped supports, each adapted to accept the placement of an element there between to yield in the direction of element positioned through the opening for resilient engagement with the element.
FIGS. 1-10 of U.S. Pat. No. 4,299,363 shows a connector formed from a resiliently flexible material with a plurality of jaws directed toward the axis center of the connector to resiliently seat against the inserted cable to oppose withdrawal of the cable from the connector.
FIG. 2 of the U.S. Pat. No. 5,410,104 discloses a low profile connector compressible grommet for use in a connector having internally inclined surfaces with a plurality of ribs spaced about the periphery of a sleeve with spaces between the apexes.
These connectors are typically pushed or otherwise inserted into an opening in the enclosure such as a knock-out of an electrical outlet box or panel. Once the connector is in place, a wire or cable is then pushed through its center and into the enclosure for subsequent termination with an electrical device or fixture inside the box. The connector itself is generally configured with a plurality of inwardly extending fingers that engage and grip the wire and which permit the wire to be pushed into the box but which make it difficult to pull the wire back out of the box. Hence such connectors not only help isolate the wire from the sharp edges of the knock-out, but they also provide strain relief by transferring the wire withdrawal force to the enclosure itself rather than allowing such force to proceed to the terminated end of the wire and thus to the device to which the wire is connected.
Most such connectors are made of plastic as in the '363 patent, but metal connectors exist as well (see, for example, the '409 patent). Also, such connectors are generally of one piece construction, but multiple piece connectors have also been devised as shown in the above '104 patent.
However, although most such devices may be suitable at providing strain relief to the inserted wire, their construction, and particularly their flexible finger component, is such that they are unable to also seal around the wire and provide weather protection in order to prevent moisture from passing into the box. One exception to this is the '104 patent which both seals and provides strain relief. However, this patent seals via a grommet that is compressed between a connector body and a threaded end cap is provided as an extra part in the normal fashion. Hence, to effect a seal according to this patent, more than simply inserting the wire through the strain relief connector is required. Instead, the user must also assemble the grommet into the connector body located on one side of the enclosure and tighten the threaded end cap onto the connector body, this threaded end cap being on the other side of the enclosure.
Such ready access to both sides is not always possible due to the tight constraints and limited room in typical electrical enclosures. Furthermore, such assembly and installation steps increase the expense of using this connector. Additionally, the end cap itself is bulky and extends into the interior of the enclosure which may either interfere or cause interference with other devices therein. Also, the grommet size limits the range of wire gauges that can be used with this connector and still seal and seat properly.